Gerlier studied at the seminary in Fribourg before serving as an officer of the French Army in World War I, during which he was wounded and captured.

He received his episcopal consecration on the following 2 July from Cardinal Louis-Ernest Dubois, with Bishops Benjamin Roland-Gosselin and Maurice Dubourg serving as co-consecrators, in Notre Dame Cathedral.

During World War II, Gerlier condemned Pierre Laval's deportation of Jews to Nazi death camps,[1] the severe conditions of which he also opposed.

[2] For his efforts to save Jews during World War II he was posthumously awarded the title Righteous among the Nations by Yad Vashem in 1981.

Living long enough to attend only the first three sessions of the Second Vatican Council, Gerlier was also a cardinal elector in the conclave of 1963 that chose Pope Paul VI.